Synthetic Aperture Radar (SAR) imaging systems are widely used in aerial and space reconnaissance. Usually, an aircraft or a spacecraft is provided with a SAR imaging system which transmits radar pulses and collects radar echoes corresponding to the radar pulses reflected by a target area to be imaged.
Due to the large amount of data generated by a SAR system, optical solutions have been developed for processing the SAR raw data. For example, an image from the SAR raw data can be generated by optical signal processing using a spatial light modulator. However, wavefront aberrations may occur in the SAR optical signal processing system due to variations of optical parameters due for example to manufacturing tolerances, misalignment of optical components, temperature changes, vibrations and degradations caused by launch and in-flight conditions. Parameter variations in the SAR imaging system, such as an altitude change or a change in the atmosphere for example, may also result in wavefront aberrations. In some optical SAR signal processing systems, the position of optical components may be varied in order to compensate for such parameters variations. However, the requirement for moving the optical components reduces the sturdiness and viability for the optical SAR raw signal processing system.
Therefore there is a need for a method and a system for compensating for a parameter variation in a SAR imaging system.